The present invention relates to a process for manufacturing composite materials from which, after a forming operation by hot pressing, components or panels having improved properties are produced.
The advantages associated with the use of sheets or laminates of composite materials using a mixture of wood and textile fibre are of common knowledge, in particular the production which includes a hot pressing operation of items of a stabilized shape, as opposed to similar items produced from a simple wood agglomerate.
The hot press forming of wood agglomerates encounters major moulding problems, the solution of which cells for a pre-forming stage and, even then, the production of complicated shapes is extremely difficult. Furthermore the resulting product lacks flexibility when using pure agglomerates, and is relatively poor in its thermal and accoustic characteristics.
The substitution of composite material using a wood fibre and a textile fibre mixture, the latter being of any nature, for a simple wood agglomerate has well proven advantages but the manufacturing processes which have been tried or installed to date have been uneconomic and the results have been unsatisfactory.
The diverse mechanical processes for defibrating wood are not readily cost-effective and do not land themselves easily to avoiding the agglomeration of the fibres arising from the presence of natural resins in the wood itself and which have to be eliminated so as to allow a subsequent satisfactory mixture of the wood fibres with other fibrous material.
Also, it is difficult to produce, when using wood defibration processes, fibres of an average length suitable for mixing with textile fibres for the production of laminates by conventional means.
In view of the above, to obtain an acceptable cost effectiveness, short wood fibres, specifically 2 to 5 mm. have to be produced, and there are not readily suitable for utilization by the conventional processes, which normally require a minimum length of 10 millimeters.
Secondly, the mixing of the wood fibres with the textile fibres must be virtually perfect so as to obtain complete homogeneity in the product and the required characteristics in the final material, utilizing the short wood fibres while avoiding their being broken in the course of manufacturing the sheet or laminate of the composition material.